Beach nourishment and sedimentary plumes in the bay of Aigues-Mortes (Languedoc-Roussillon, France). Storm impacts on sedimentary hydrodynamics

Yann Leredde (1) , Héloise Michaud (2) , Eric Berthebaud (1) , Christine Lauer-Leredde (3) , Patrick Marsaleix (2) , C. Estournel (2) , Bénédicte Guérinel , Sébastien Thorin , Thibault Schwartz , Cécile Richard

1 Géosciences Montpellier - Risques
2 LAERO - Laboratoire d'aérologie
3 Bassins

In the bay of Aigues-Mortes, the managers of the co astal cities try to preserve the socio-economic and patrimonial stakes against the coastal hazards, such as contamination, storm surge and erosion. In this context, a massive beach nourishment of sand (1 million of m3 for 10km of coastline) was made at the beginning of year 2008 to reduce erosion. The REPBAM project (REchargements et Panaches sédiment aires dans la Baie d'Aigues-Mortes) aims to qualify and quantify by in-situ measurements and numerical modelling: 1. the geomorphological evolution of this modified coast and 2. the impact of the sediment's resuspension on the coastal ecosystems, in particular the one of the Posidonia oceanica seagrass. A numerical modelling "wave/current/sediment" is first implemented for December 2008. Nested and curvilinear grids allow a very high resolution for the beach area but also include the inner shelf where the seagrasses are located. Hydrodynamic and topo-bathymetric measurements were acquired from January to May 2012. Model and measurements results show the same trends during storms: strong currents, seaward migrationof the innerbar, sediment resuspension and turbid on the inner shelf.

Mots clés: Posidon ia oceanica seagrass; turbidity; plume; storm; beach nourishment

Domaines: Océan, Atmosphère

Yann Leredde, Héloise Michaud, Eric Berthebaud, Christine Lauer-Leredde, Patrick Marsaleix, et al.. Beach nourishment and sedimentary plumes in the bay of Aigues-Mortes (Languedoc-Roussillon, France). Storm impacts on sedimentary hydrodynamics. Coastal Dynamics 2013 7th international conference of Coastal Dynamics, Jun 2013, Arcachon, France. pp.1183-1194, 2013, ⟨10.13140/2.1.4283.3601⟩. ⟨hal-00908082⟩